Heat is widely used to treat various types of illness and injury. Heated garments or pads of various sizes and shapes often are used to apply heat to a given area of the body affected by the illness or injury.
Many heating pads simply store heat energy from an external source, such as an oven, but the heat from these types of devices dissipates and eventually disappears completely. Consequently, these devices quickly lose their effectiveness.
Other types of heating pads include an internal heat source that can provide continuous heat, but these devices typically rely on electricity and resistance heating to power the internal heat source. Cords or bulky batteries are required to provide the necessary electricity. Such cords or batteries can interfere with a patient's mobility and also expose the patient to a risk of electrocution or strangulation.
Thus, current methods of heating a garment or pad are often cumbersome and ineffective, and there is a need for a system that can provide continuous heat without electrical cords or batteries.
Induction heating is a well-known method for producing heat in an object without the need for wires or batteries, and has been used for some time in such diverse applications as cooking appliances and welding tools. See, e.g., U.S. Pat. No. 6,124,581 (issued Sep. 26, 2000), U.S. Pat. No. 6,727,483 (issued Apr. 27, 2004). In general an induction heating system requires a coil and an alternating electrical current. When connected to the alternative electrical current, the coil produces a varying magnetic field. In turn, the magnetic field induces an electric current in an object when the object is placed within the magnetic field. The resistance to electric current in the object causes the object to emit heat.
Notwithstanding current applications of induction heating, though, no known product applies the principles of induction heating to address the need for a garment or pad that can provide continuous heat without electrical cords or batteries.